Some users of the FCM V1 Batch Send API experienced an elevated number of 401 errors (CREDENTIALS_MISSING) being returned.
The issue has been mitigated.
Firebase Status Dashboard
This page provides status information on the services that are part of Firebase. Check back here to view the current status of the services listed below. If you are experiencing an issue not listed here, please contact Support. Learn more about what's posted on the dashboard in this FAQ. For additional information on these services, please visit https://firebase.google.com/.